Following circumscribed monocular retinal lesions most cells located in the lesion projection zone (LPZ) in the cat’s primary visual cortices remain binocular but their receptive fi elds (RFs) revealed by stimulation via the lesioned eye, are displaced into proximity of the lesion. The process of topographic reorganization (adaptive learning) of the visual cortex, is based on spike timing-dependent plasticity rather than the classical Hebbian rules [Young et al. (2007) Nat Neurosci 10: 887–895]. The contrast sensitivities of the classical RFs of LPZ neurons revealed by stimulation via the lesioned eye are signifi cantly lower, while the suppresive infl uences of their “silent”, extra-classical RFs are weaker than those of their counterparts revealed by stimulation via non-lesioned eye. Other properties (e.g. orientation, spatial and temporal frequency preferences) however match well the properties of RFs revealed by stimulation via non-lesioned eye. These similarities are presumably visual experience-dependent, that is, they are related to the fact that in the post-lesion period (from adolescence to maturity), the neuronal activities originating from each retina are correlated by effectively synchronized exposure to the same visual stimuli. These results are consistent with the hypothesis that the ectopic RFs are based on enhancement of the synaptic effi cacy of long-range, excitatory intracortical connections. Financial support: Nencki Institute, Poland; NHMRC and ARC grants, Australia.
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